This invention relates to an electronic weight measuring device provided with a load cell.
Heretofore, there have generally been known electronic weight measuring devices having a load cell and an A/D converter for converting an output signal of the load cell into a digital value. In an electronic weight measuring device of this type, the load cell produces a unipolar, e.g. positive, output signal corresponding to the weight of load applied, while the A/D converter produces a digital signal corresponding to the positive output signal from the load cell. The digital signal from the A/D converter is processed on a microcomputer by a well-known method, and then supplied to a display unit.
Thus, according to the prior art device, produced from the load cell is e.g., a positive output voltage within a range corresponding to a predetermined measuring range, which is supplied as an input signal to the A/D converter, so that it is required that the range of the input voltage of the A/D converter be enlarged in proportion to the measuring range, that is, it is required that the resolution power of the A/D converter be made larger than that of the weight measuring device.
An object of this invention is to provide an electronic weight measuring device which includes an A/D converter for converting positive and negative input signals into digital signals and which supplies the A/D converter with an input signal within a range defined by positive and negative values and corresponding to a weight measuring range, thereby reducing the range of the absolute value of the input signal for the A/D converter.